The Court of Appeal last week considered the change in the UK law of patent infringement following the Supreme Court decision in Actavis v Lilly.

Despite an ultimate finding that Ice-World's patent was invalid, on infringement, Icescape’s temporary ice-rink would have infringed as an immaterial variant.

Reiterating the new 'markedly different' approach to questions of infringement, Lord Justice Kitchin reminded us that the issue is now addressed by asking: (i) does the variant infringe any of the claims as a matter of normal interpretation; and, if not, (ii) does the variant nonetheless infringe because it varies from the invention in a way which is immaterial? If the answer to either issue is “yes”, there is an infringement; otherwise, there is not.

The meaning of 'normal' interpretation was initially a matter of debate. Kitchin, agreeing with early interpretations of the High Court , confirmed 'normal' must mean 'purposive'. As the claims in this case were limited to 'series connections', Icescape's 'parallel connections' did not fall within the claims at the first stage, purposive approach.

Kitchin rolled straight into an assessment of whether Icescape's variant nevertheless differed from the claim in an immaterial way. Leaving the language of the claim behind, the three Actavis questions were considered:

1. as the 'inventive core' of the patent was the flexible connection between pipes, Icescape's 'parallel' system achieved substantially the same result in substantially the same way at the 'series' connection;2. knowing what result is achieved, the way Icescape's system achieves it would be entirely obvious to the skilled person; and3. there was no reason to conclude that the patentee intended strict compliance with the claim was an essential requirement of the inventive concept.

Counsel for Icescape argued that, as Ice-World were permitted on appeal to run infringement by equivalence, Icescape should be permitted to rely on the prosecution history of the patent. This was a bold move considering the short shrift parties have faced when seeking recourse to the prosecution file. Remarkably, the judges agreed to consider relevant parts of the prosecution history, only to decide it fell well below the standard set by the Supreme Court in Actavis. It therefore did not alter the preliminary conclusion that the Icescape rink infringed the Patent.

Unfortunately for Ice-World, succeeding on infringement was a case of too little, too late. The Patent was not entitled to priority and was ultimately revoked due to intervening prior use. In addition, the groundless threats claim was upheld, as Ice-World had failed to make good the defence that it had 'no reason to suspect the patent was invalid'.

Lord Justices Kitchin and Floyd both acknowledged the sea change following Actavis. Whilst duly applying the reformulated infringement questions, the judges maintained that the claims continue to have an important function and are "the starting point for any infringement analysis". The judgment also highlighted a number of unresolved issues, including the approach to interpretation of claims when dealing with validity as opposed to infringement, as well as the approach to inventive variants. Preliminary thoughts are appearing from the High Court but we await an appeal decision to tackle these issues head on.